Electron discharge device



Sept. 17, 1963 4A. J. FIEDOR ETAL ELEcTEoN DISCHARGE DEVICE Filed Aug. l1. 1960 orf-)rey United States Patent O 3,104,341 ELECTRN DISCGE DEVICE Adolph J. Fiedor, Palo Alto, and Robert G. Rockwell, Menlo Park, Calif., assignors to Varian Associates, Palo Alto, Calif., a corporation of California Filed Aug. 11, 1969, Ser. No. 48,889 7 Claims. (Cl. S15-5.48)

This invention relates in general to high frequency emissive devices and more particularly to a novel improved electron tube.

The present invention is embodied for the purposes of disclosure in a Ku-band klystron amplifier which, because it is electrosatically focused, and thereby requires no magnet, weights only about eight ounces and is well suited for aerial navigation systems in which weight is a prime factor. One such tube has been built with four tunable resonator cavities spaced along the electron beam having a C.W. power output from 1-25 watts with a gain of approximately 30 decibels.

In order to produce a tube of such small size with sufficient gain and output power it was necessary to design a novel tuner which is small and compact in size, allows locking, yet will allow easy tuning with no backlash.

It is, therefore, the main object of the present invention to provide a small, rugged, high power and gain klystron incorporating novel tuning mechanism.

One feature of the present invention is the provision of a small, compact, positive locking tuner which is easy to tune yet has no backlash.

Another feature of the present invention is the provision of an actuating nut which serves to provide motion for the tuning diaphragm and to lock the tuner -rod into position.

Another feature of the present invention is the provision of a pair of displaced but opposed slots cut in the actuating nut of the novel tuner, normal to the axis of rotation, which allows a clamping action to lock the tuner.

Another feature of the present invention is to provide a tuning method which lends itself easily to quickly and accurately align the tube to the desired operating frequency within the tuning range of the present tube.

These and other features and advantages of the present invention will be more apparent upon a perusal of the following specification taken in connection with the accompanying drawings wherein:

FIG. 1 is an isometric view of a `klystron tube made in accordance with the present invention,

FIG. 2 is an enlarged cross-section taken along line 2 2 in FIG. l, v

FIG. 3 is an enlarged liront view partially broken away of the novel tuner apparatus, and

FIG. 4 is a cross-sectional view of a single tuner taken along line 4-4 in FIG. 3 in the direction of the arrows.

Referring now to FIGS. l, 2 and 3, the klystron made in accordance with the present invention includes a central body portion 11 which is made from a unitary block of metal having a longitudinal bore extending therethrough. Hollow cylindrical drift tubes 12, having circular resonator grids 13 on the ends thereof, are positioned within the longitudinal bore of central body portion 11 by outwardly extending annular Iheaders 15. The walls of drift tubes 12 are parallel to the axis of the electron beam passing therethrough. Fixedly secured as by brazing in one end of the longitudinal bore of the central body portion 11, is a narrow, annular anode structure 17, having a resonator grid 18 positioned in the aperture therethrough. Within the other end of central body portion 11 is an annular header 19 with a resonator grid 21 positioned in the aperture therethrough. By positioning the resonator grid 13 3,104,341 Patented Sept. 17, 1963 fice within the anode structure 17 the resonator grid 18 serves as an anode portion thereby minimizing the distance a focused electron beam must traverse through the klystron tube.

Within the central body portion 11, annular anode structure 17 and first annular header-.15 on the first drift ltube 12 define a singly reentrant first cavity resonator 22.

Three doubly reentrant cavity resonators 23 are defined by the annular headers 15 and annular header 19.

-Fixedly secured, as by brazing, to the central body portion 11 and sealing off the end thereof adjacent to the anode structure 17 is a beam generating assembly 26 including hollow cylindrical focus electrode 27.

The beam collector assembly 41 includes a hollow cylindrical end portion 42 closed at its outward end and lixedly secured to the end of central body portion 11 adjacent the annular header 19 by a braze therebetween. Beam collector assembly 41 also includes a fin assembly comprising annular fin members 45 brazed to the cylindrical end portion 42 whereby the tube is air cooled. It is noted that central body portion 11 is provided with a fin assembly to further aid in air cooling the entire devi-ce thereby removing the necessity of an internal liquid cooling system. An evacuation pinch-off tube 46 is provided in the closed end portion 42 with four entrants 46' into the collector cavity for pumping the tube. It is further noted that a conical member 47 is provided at the closed end l of beam collector assembly 41 to diffuse the electron beam striking the end of beam collector assembly 41 thereby reducing the possibility of secondary electrons released by impinging primary electrons from entering into the drift tube and cavity section of central body portion 11.

Identical input and output waveguides 48 and 49 respectively are secured to the central body portion 11 and respectively communicate with the first cavity resonator 22 and the third double reentrant cavity resonator 23 through milled openings, not shown, within central body portion 11. IThe outwardly projecting end of each waveguide is provided with a wavequide flange member 51 which carries a ceramic Window 52 sealed therein by a Window frame 53.

Machined into one side of main body portion 11 are four quasi-elliptical apertures which provide for tuning diaphragms for tuning each of the resonant cavities. A thin movable walled metal sheet or member 61 convoluted to form four tuner idiaphragrns 62 forms the tunable portion on a side of each of the four cavities. This metal `sheet 61 is brazed to a diaphragm block 65 in which four quasi-elliptical holes have been formed. Brazed to the outer side of each tuner diaphragm 62 is the inward end of a connecting or tuner rod 63 which is provided with a quasi-elliptical stop plate 64 brazed to its outer end (see FIG. 4). Stop plate 64 is slidably fitted Within the quasi-elliptical holes in diaphragm block 65. Diaphragrn block 65 is furthe-1' provided with a shoulder 65 in each of the quasi-elliptical holes to provide a tuning stop for inward motion of the tuning rods 63. Brazed to the outer side of stop plate 64 is a screw 66 which passes through the inner end ofone of four holes ydrilled in Ia tuner mounting block 67. The bottom of each hole is provided with a shoulder 67 which serves as a tuning stop for outward motion of tuning rod 63. Screw 66 is movably captured by an actuating nut or member 68, a hollow cylinder provided with internal threads at its inner end for mating with lscrew 66. Actuating nut 68` is also provided with transverse compressible slots normal to the axis of rotation of actuating nut 68. At its outer er1-d, actuating nut 68 is provided with an access entry for` :a tuning tool such as an Allen wrench for imparting motion to the actuating nut 68 which is thereby transmitted to tuner rod 63. The outer portion of each off the holes within mounting block 67 is threaded to Iaccommodate the external threads of tuner lock nut 69. Tuner lock nut or nut means 69 is provided with slots at its outer end to accomrnodate a tuning tool. Tuner lock nut 69 is hollow to allow passage therethrough of the tuning tool for actuating nut 68. v

Tuner lock nut 69 is screwed `down upon actuating nut 65. As pressure is applied to actuating nut 68 a clamping action occurs upon screw 66 of the tuning rod. It is noted that the clamping action occurs from two directions, first from the outward end of actuating nut 68 due to the inward force of tuner` lock nut 69 and seco-nd from the bottom or shoulder67, which acts as a ground plane.

These two opposite and equal forces act on the opposite sides of the screw thread and prevent backlash but allow subsequent tuning. Normally this is done at the factory and re-setting of tuner lock nut 69 is not again required.

'To tune the cavity resonator, a tuning tool is inserted in the access entry of actuating nut 68 to turn nut `68 and thereby impart lateral movement to tuner rod 63. The quasi-elliptical hole cut in tuner diaphragm block 65 in which stop plate 64 is slid-ably mounted prevents twisting and turning of the diaphragm due to torque when rotating the actuating nut e3. The shoulder provided in the bottom of the holes in mounting block 67 prevents 4excessive outward tuning While the shoulder provided in diaphragm tuner block 65 prevents excessive inward tuning.

It is noted that actuating nut 68 serves the dual purpose of (l) providing lateum movement to the tuning rod and (2) to provide the clamping action to secure screw 66 into its desired position and prevent backlash.

What has been shown .is a new. klystron amplier having no increase in weight or size over the previous light weight OW. medium power level tubes yet Ian increase in gain has been accomplished due to increasing beam bunching by increasing the number of cavities within the tube structure.

Vlt is here noted that the novel tuning structure may be equally Well adapted and used in other types of klystrons.

Since many changes could be made in the above construction, and many apparently Widely different embodiments of this invention could be made Without departing from the scope thereof it 'is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illlustrative and not in a limiting sense.

What is claimed is:

1. In an electron discharge device including ya cavity resonator having a movable wall portion, tuning means for moving said wall portion, said tuning -means including fa threaded tuner rod means att-ached to the outside surface of the movable wall; said tuner rod means movably captured by a rotatable threaded actuating membe to impart movement to `said tuner rod means, said actuating member having axially compressib'le slot openings therein, said slot openings being substantially normal to the axis of rotation of said actuating member, and compressing means communicating with said actuating member to impart pressure thereon thereby causing a clamping yaction from said actuating member upon said tuner rod means thereby locking said tuner rod means in position.

2. The device according to claim 1 wherein said threaded rod means includes a screw and wherein said actuating member includes an elongated nut having a pair lof opposed staggered slots.

3. in an electron discharge device including a cavity resonator having a movable wall tuning means for movin-g said movable wall thereby tuning said cavity reonator, said tuning means including a tuner rod, a stop plate and screw means, said tuner rod secured to the outside surface of said movable wall, said stop plate secured to the outside of said tuner rod, said stop plate slidably captured by -a diaphragm block member which acts to prevent axial ro- :tation of said stop plate and said tuner rod; said screw` means attached to the outside of said stop plate, said screw means being captured by a rotatable actuating member to impart lateral movement to said tuning means, said rotatable actuating member including axially compressible slots substantially normal to the axis of rotation of sai-d actuating member', said actuating member being movably captured by a tuner block member, said tuner block member movably accommodating pressure means communicating with said actuating member to iinpart a clamping action upon said screw means thereby securing said tuning means into its desired position.

4. The device according to claim 3 wherein said actuating member includes a hollow cylinder having a pair of opposed compressible slots therein, said slots being comprcssible under force and thereby impart pressure upon ythe captured screw means of the tuner rod.

5. Tuning means for `cavi-ty resonators including a movable wall comprising, in combination; a tuner rod means attached to the outside surface of the movable wall, said tuner rod means including a stop plate and a threaded outer portion, said stop plate being slidably captured by a diaphragm block member which acts to prevent axial rotation of said stop plate and said tuner rod, said diaphragm block member further including means to prevent excessive inward motion of said tuner rod, said threaded outer portion of said tuner rod being 4captured by a rotatable threaded actuating member to impart lateralmovemeut to said tuning rod, said rotatable threaded actuating member includes an elongated internally threaded nut having a pair of opposed, staggered axially compressible slots cut therein, said slots being substantially normal to the axis of rotation of said actuating member, said actuating member Ifurther being movably captured by a tuner block member, said tuner block member movably accommodating pressure means communicating with said actuating member to impart Ya clamping action upon said threaded outer portion of said tuner rod and said tuner block member further including stop means to prevent excessive outward motion of said tuner rod.

6. In apparatus as herein described including a movable member, connecting rod means for moving said movable member, said connect-ing rod means being at least partially threaded, an actuating member threadably mati ing with said connecting rod means, said actuating member serving as locking means and including at least one deformable portion, said portion having a slot extending at an angle to the longitudinal axis of said connecting rod, nut means for engaging said actuating member to impart pressure thereon to ydistort said deformable portion and cause a clamping action of the latter upon said connecting rod thereby preventing unwanted movement for engaging said actuating member to impart pressure thereon to distort said deformable portion and cause a clamping action of the latter upon said moving means thereby preventing unwanted movement from said movable member.

References Cited in the le of this patent UNITED STATES PATENTS 2,7o1,32.1 Rich Feb. 1, 1955 2,824,258 snow er a1. Feb. 18, 1958 2,862,138 Larkin Nov. 25, 1958 

7. THE APPARATUS AS HEREIN DESCRIBED INCLUDING A MOVABLE MEMBER, MEANS FOR MOVING SAID MOVABLE MEMBER, SAID MEANS BEING AT LEAST PARTIALLY THREADED, AN ACTUATING MEMBER THREADABLY MATING WITH SAID LAST NAMED MEANS, SAID ACTUATING MEMBER SERVING AS LOCKING MEANS AND INCLUDING AT LEAST ONE DEFORMABLE PORTION, MEANS FOR ENGAGING SAID ACTUATING MEMBER TO IMPART PRESSURE THEREON TO DISTORT SAID DEFORMABLE PORTION AND CAUSE A CLAMPING ACTION OF THE LATTER UPON SAID MOVING MEANS THEREBY PREVENTING UNWANTED MOVEMENT FROM SAID MOVABLE MEMBER. 